feat(all): Improve sendmail transport error handling

lettre/src/sendmail/error.rs

@@ -2,6 +2,7 @@
 
 use self::Error::*;
 use std::io;
+use std::string::FromUtf8Error;
 use std::{
     error::Error as StdError,
     fmt::{self, Display, Formatter},
@@ -11,7 +12,9 @@ use std::{
 #[derive(Debug)]
 pub enum Error {
     /// Internal client error
-    Client(&'static str),
+    Client(String),
+    /// Error parsing UTF8in response
+    Utf8Parsing(FromUtf8Error),
     /// IO error
     Io(io::Error),
 }
@@ -25,7 +28,8 @@ impl Display for Error {
 impl StdError for Error {
     fn description(&self) -> &str {
         match *self {
-            Client(err) => err,
+            Client(ref err) => err,
+            Utf8Parsing(ref err) => err.description(),
             Io(ref err) => err.description(),
         }
     }
@@ -33,6 +37,7 @@ impl StdError for Error {
     fn cause(&self) -> Option<&StdError> {
         match *self {
             Io(ref err) => Some(&*err),
+            Utf8Parsing(ref err) => Some(&*err),
             _ => None,
         }
     }
@@ -44,9 +49,9 @@ impl From<io::Error> for Error {
     }
 }
 
-impl From<&'static str> for Error {
-    fn from(string: &'static str) -> Error {
-        Error::Client(string)
+impl From<FromUtf8Error> for Error {
+    fn from(err: FromUtf8Error) -> Error {
+        Utf8Parsing(err)
     }
 }
 

lettre/src/sendmail/mod.rs

@@ -70,8 +70,7 @@ impl<'a> Transport<'a> for SendmailTransport {
         if output.status.success() {
             Ok(())
         } else {
-            // TODO display stderr
-            Err(error::Error::Client("The message could not be sent"))?
+            Err(error::Error::Client(String::from_utf8(output.stderr)?))
         }
     }
 }

lettre/src/smtp/authentication.rs

@@ -10,7 +10,7 @@ pub const DEFAULT_ENCRYPTED_MECHANISMS: &[Mechanism] = &[Mechanism::Plain, Mecha
 /// Accepted authentication mechanisms on an unencrypted connection
 pub const DEFAULT_UNENCRYPTED_MECHANISMS: &[Mechanism] = &[];
 
-/// Convertable to user credentials
+/// Convertible to user credentials
 pub trait IntoCredentials {
     /// Converts to a `Credentials` struct
     fn into_credentials(self) -> Credentials;

lettre/src/smtp/client/mod.rs

@@ -123,22 +123,19 @@ impl<S: Connector + Write + Read + Timeout + Debug> InnerClient<S> {
 
     /// Tells if the underlying stream is currently encrypted
     pub fn is_encrypted(&self) -> bool {
-        match self.stream {
-            Some(ref stream) => stream.get_ref().is_encrypted(),
-            None => false,
-        }
+        self.stream
+            .as_ref()
+            .map(|s| s.get_ref().is_encrypted())
+            .unwrap_or(false)
     }
 
     /// Set timeout
     pub fn set_timeout(&mut self, duration: Option<Duration>) -> io::Result<()> {
-        match self.stream {
-            Some(ref mut stream) => {
-                stream.get_mut().set_read_timeout(duration)?;
-                stream.get_mut().set_write_timeout(duration)?;
-                Ok(())
-            }
-            None => Ok(()),
+        if let Some(ref mut stream) = self.stream {
+            stream.get_mut().set_read_timeout(duration)?;
+            stream.get_mut().set_write_timeout(duration)?;
         }
+        Ok(())
     }
 
     /// Connects to the configured server

lettre/src/smtp/client/net.rs

@@ -92,8 +92,11 @@ impl Write for NetworkStream {
 /// A trait for the concept of opening a stream
 pub trait Connector: Sized {
     /// Opens a connection to the given IP socket
-    fn connect(addr: &SocketAddr, timeout: Option<Duration>, tls_parameters: Option<&ClientTlsParameters>)
-        -> io::Result<Self>;
+    fn connect(
+        addr: &SocketAddr,
+        timeout: Option<Duration>,
+        tls_parameters: Option<&ClientTlsParameters>,
+    ) -> io::Result<Self>;
     /// Upgrades to TLS connection
     fn upgrade_tls(&mut self, tls_parameters: &ClientTlsParameters) -> io::Result<()>;
     /// Is the NetworkStream encrypted

lettre/src/smtp/response.rs

@@ -174,7 +174,7 @@ impl Response {
     /// Returns only the first word of the message if possible
     pub fn first_word(&self) -> Option<&str> {
         self.message
-            .get(0)
+            .first()
             .and_then(|line| line.split_whitespace().next())
     }
 

lettre_email/src/lib.rs

@@ -297,10 +297,7 @@ impl EmailBuilder {
     pub fn text<S: Into<String>>(self, body: S) -> EmailBuilder {
         let text = PartBuilder::new()
             .body(body)
-            .header((
-                "Content-Type",
-                mime::TEXT_PLAIN_UTF_8.to_string(),
-            ))
+            .header(("Content-Type", mime::TEXT_PLAIN_UTF_8.to_string()))
             .build();
         self.child(text)
     }
@@ -309,10 +306,7 @@ impl EmailBuilder {
     pub fn html<S: Into<String>>(self, body: S) -> EmailBuilder {
         let html = PartBuilder::new()
             .body(body)
-            .header((
-                "Content-Type",
-                mime::TEXT_HTML_UTF_8.to_string(),
-            ))
+            .header(("Content-Type", mime::TEXT_HTML_UTF_8.to_string()))
             .build();
         self.child(html)
     }
@@ -325,18 +319,12 @@ impl EmailBuilder {
     ) -> EmailBuilder {
         let text = PartBuilder::new()
             .body(body_text)
-            .header((
-                "Content-Type",
-                mime::TEXT_PLAIN_UTF_8.to_string(),
-            ))
+            .header(("Content-Type", mime::TEXT_PLAIN_UTF_8.to_string()))
             .build();
 
         let html = PartBuilder::new()
             .body(body_html)
-            .header((
-                "Content-Type",
-                mime::TEXT_HTML_UTF_8.to_string(),
-            ))
+            .header(("Content-Type", mime::TEXT_HTML_UTF_8.to_string()))
             .build();
 
         let alternate = PartBuilder::new()